skip to main content


Title: Water Vapor and Alcohol Vapor Induced Healing of the Nanostructured KBr Surface
NSF-PAR ID:
10369499
Author(s) / Creator(s):
 ;  ;  
Publisher / Repository:
American Chemical Society
Date Published:
Journal Name:
The Journal of Physical Chemistry C
Volume:
126
Issue:
31
ISSN:
1932-7447
Page Range / eLocation ID:
p. 13433-13440
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
More Like this
  1. Abstract Transition metal dichalcogenides (TMDs) are known for their layered structure and tunable functional properties. However, a unified understanding on other transition metal chalcogenides (i.e. M 2 X) is still lacking. Here, the relatively new class of copper-based chalcogenides Cu 2 X (X = Te, Se, S) is thoroughly reported. Cu 2 X are synthesized by an unusual vapor–liquid assisted growth on a Al 2 O 3 /Cu/W stack. Liquid copper plays a significant role in synthesizing these layered systems, and sapphire assists with lateral growth and exfoliation. Similar to traditional TMDs, thickness dependent phonon signatures are observed, and high-resolution atomic images reveal the single phase Cu 2 Te that prefers to grow in lattice-matched layers. Charge transport measurements indicate a metallic nature at room temperature with a transition to a semiconducting nature at low temperatures accompanied by a phase transition, in agreement with band structure calculations. These findings establish a fundamental understanding and thrust Cu 2 Te as a flexible candidate for wide applications from photovoltaics and sensors to nanoelectronics. 
    more » « less
  2. ABSTRACT

    This work examines the sorption, diffusion, and polymer relaxation behavior for water and C1‐C7 alcohol vapors at 30  °C in ethylenediamine vapor‐phase crosslinked Matrimid. Ethylenediamine is sufficiently volatile that crosslinking can occur by exposing the polymeric film to saturated vapor, in contrast to more conventional means of dissolving the crosslinker in a solvent and immersing the polymeric film in the solution. The vapor‐phase exposure method avoids the use of additional solvent and undesired solvent‐induced swelling. Sorption isotherms demonstrate that water and C1‐C5 alcohols do not appreciably differ for unmodified and crosslinked Matrimid; however, an approximate 90% reduction in sorption was determined for hexanol and heptanol. A minor impact on diffusion coefficients for water, methanol, and ethanol was observed, while those of propanol and butanol were reduced over an order of magnitude. Relaxation kinetics were similarly unchanged for water and C1‐C3 alcohols, while being significantly reduced for butanol and higher alcohols. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci.2017,134, 44771.

     
    more » « less
  3. null (Ed.)